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Finding the Devils Windstorm

It was a clear, starlit night in the second week of December 2011, and long-time Eastern Sierra photographer John Dittli was hiking from June Lake to Reds Meadow after a backcountry ice-skating trip when he started to notice something strange.

At first, he and his fellow hikers thought it was just a strange—but small—event; a windstorm that hit a few trees hard.

In winter 2011 there was no snow in the high country, and the lakes were smooth as glass, which is why Dittli was out there, hiking though the cold night.

There had been a very windy night a week or so earlier, on the last day of November and the first day of December, and maybe that had brought the trees down, he thought.

“I thought if we just got over these few, it would be over,” he said.

But it wasn’t.

A little way down the trail, he ran into another big red fir, and another, and soon, dozens. By the time he began to approach the Reds Meadow area proper, the tangle of trees was in the hundreds.

“An epic ice skating trip turned into an epic scramble over hundreds of trees,” he said.

“We reached Reds Meadow and the campgrounds there and it was unbelievable; picnic tables thrown up in the air, trees down over buildings, broken roofs, rootwads of giant trees as high as I am tall. It was clear something amazing had happened.”

The small group still had to hike out from Reds Meadow up the paved road to the closed gate near Minaret Summit. As they picked their way through the starlight, the true magnitude of what would later become known as the “Devils Windstorm” became apparent.

“The road was dented, huge chunks of asphalt ripped out, big trees down,” he said. “We got to the top that morning and I called the Forest Service and I said, ‘Hey, maybe you guys should get down here and take a look.’

“No one had been down there since they closed the road in early November and they had no idea what had happened.”

With that call, the region got wind of the most extreme wind event to hit the state in recorded times—a giant windstorm that took down tens of thousands of trees in Reds Meadow valley (and affected some other areas as well) under the onslaught of winds that sometimes capped 200 miles an hour.

It took a year to clean up the mess, both on the road and trails, and today, the magnitude of the blowdown is evident to anyone who travels down into the valley.

Where once there were campgrounds shrouded in trees, there is open sky. Where once there were trails lined only with pumice and sand, there are narrow corridors through tangles of downed trees—corridors cut with chainsaw and bucksaws—and lined with hundreds of trees piled six and seven feet high.

Two years later, the Devils Windstorm continues to fascinate and challenge scientists and the public and meteorologists alike.

One of them is Chris Smallcomb, a meteorologist with the Reno-based National Weather Service office, and a specialist in tornados. He was in Mammoth Tuesday night, May 21, speaking to a packed room about the windstorm at the Sierra Nevada Aquatic Research Laboratory (SNARL) Green Church facility during one of its Green Church Lecture series.

“It’s one of the top five storms of the past 12 years and there’s no comparison, even to them,” he said, noting the duration of the storm was in the double digits, not single digits, and the wind speeds exceeded most other storms’ wind speeds.

“I like to say it’s like baking a cake,” he said. “It all depends on the ingredients as to what kind of cake you get.

“In this case, the right ingredients were present in the right amount and for the right amount of time to create an extreme wind event.”

The main ingredients, he said, were a strong high to low-pressure gradient, an accessible jet stream, and the kind of terrain to maximize a possible wind event.

“In this case, it was the terrain that really made it,” he said. “First, you have this gap in the Sierra, the San Joaquin River valley, and that means wind is funneled in a narrow channel, which means it goes even faster.

“Then you have Mammoth Mountain, which is high and very steep and which allowed the upslope winds to rise up over the crest and then slam down the other side, into Reds Meadow, where it could create of kind of rotor effect and create even more havoc.”

On top of that, he said, another condition was the stable air above the storm, which helped to hold the storm in place, giving the wind more time to do its destructive work.

The reason the whole event remained a mystery for almost two weeks after it occurred, when Dittli and his group stumbled on the downed trees, is because the weather service does not have any monitoring equipment in the valley, he said.

Monitoring equipment on Mammoth Mountain alerted the agency that a serious wind event had occurred—but the monitors top out at measuring winds at 150 miles an hour, he said.

It was only when the agency and others began to look more closely at the data from that night that they saw patterns that led them to believe the winds had reached about 200 miles an hour on the top of Mammoth Mountain, with winds as high as 125 to 150 miles an hour in Reds Meadow, making the Devils Windstorm one for the record books.